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In certain applications, conventional grounding of electromagnetic flowmeters can pose special challenges. This article illustrates those challenges and sheds light on a unique solution that is especially suitable for problematic applications, some of which are found in desalination facilities. An example of a successful chemical application is provided.

For many decades, electromagnetic flowmeters (EMFs) have been the first choice for measuring the volumetric flow of electrically conductive liquids. This is true for many industries such as chemical, pharmaceutical, food, beverage and throughout the water/wastewater industry.

The basis of the measuring principle is Faraday's Law of Induction, wherein an induced voltage at the electrodes is proportional to the velocity of a conductive fluid movingwithin a magnetic field. The inner wall of the measuring tube must be electrically isolated and only the electrodes are in contact with the fluid. Thus, most EMF measuring tubes are lined with hard rubber or other elastomers, or in cases where the fluids are extremely corrosive, they can be made entirely of ceramic.